scholarly journals Model behavior of arbuscular mycorrhizal fungi: predicting soil carbon dynamics under climate change

Botany ◽  
2016 ◽  
Vol 94 (6) ◽  
pp. 417-423 ◽  
Author(s):  
Kathleen K. Treseder
Keyword(s):  
Climate Change ◽  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Earth System ◽  
Soil C ◽  
System Models ◽  
Microbial Groups ◽  
Earth System Models

In this commentary, I advocate for more detailed incorporation of arbuscular mycorrhizal (AM) fungi in Earth system models, to improve our projections of global climate change. Current Earth system models display relatively low predictability of soil C stocks, which limit our ability to estimate future climate conditions. A more explicit incorporation of microbial mechanisms can increase the accuracy of ecosystem-scale models that inform the larger-scale Earth system models. Of the numerous microbial groups that can influence soil C dynamics, AM fungi are particularly tractable for integration in models. Arbuscular mycorrhizal fungi are globally abundant and perform critical roles in C cycling, such as augmentation of net primary productivity and soil C storage. Moreover, AM communities exhibit relatively low diversity within ecosystems, compared with other microbial groups. In addition, global datasets of AM ecology are available for use in model development. Thus, AM communities can be readily simulated in next-generation trait-based models that link microbial diversity to ecosystem function. Altogether, we are well-poised to incorporate the dynamics of individual AM taxa in ecosystem models, which can then be coupled to Earth system models. Hopefully, these efforts would advance our ability to predict and plan for future climate change.

Assessing the capacity of Earth System Models to simulate spatiotemporal variability in fire weather indicators

2021 ◽  
Author(s):  
Carolina Gallo Granizo ◽  
Jonathan Eden ◽  
Bastien Dieppois ◽  
Matthew Blackett
Keyword(s):  
Climate Change ◽  
Spatial Scales ◽  
Fire Danger ◽  
Spatiotemporal Variability ◽  
Global Evaluation ◽  
Fire Weather ◽  
Earth System ◽  
Fire Weather Index ◽  
System Models ◽  
Earth System Models

<p>Weather and climate play an important role in shaping global fire regimes and geographical distributions of burnable areas. At the global scale, fire danger is likely to increase in the near future due to warmer temperatures and changes in precipitation patterns, as projected by the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). There is a need to develop the most reliable projections of future climate-driven fire danger to enable decision makers and forest managers to take both targeted proactive actions and to respond to future fire events.</p><p>Climate change projections generated by Earth System Models (ESMs) provide the most important basis for understanding past, present and future changes in the climate system and its impacts. ESMs are, however, subject to systematic errors and biases, which are not fully taken into account when developing risk scenarios for wild fire activity. Projections of climate-driven fire danger have often been limited to the use of single models or the mean of multi-model ensembles, and compared to a single set of observational data (e.g. one index derived from one reanalysis).</p><p>Here, a comprehensive global evaluation of the representation of a series of fire weather indicators in the latest generation of ESMs is presented. Seven fire weather indices from the Canadian Forest Fire Weather Index System were generated using daily fields realisations simulated by 25 ESMs from the 6<sup>th</sup> Coupled Model Intercomparison Project (CMIP6). With reference to observational and reanalysis datasets, we quantify the capacity of each model to realistically simulate the variability, magnitude and spatial extent of fire danger. The highest-performing models are identified and, subsequently, the limitations of combining models based on independency and equal performance when generating fire danger projections are discussed. To conclude, recommendations are given for the development of user- and policy-driven model evaluation at spatial scales relevant for decision-making and forest management.</p>

scholarly journals Response of Arbuscular Mycorrhizal Fungi to Simulated Climate Changes by Reciprocal Translocation in Tibetan Plateau

2015 ◽  
Vol 43 (2) ◽  
pp. 488-493
Author(s):  
Zhaoyong SHI ◽  
Xubin YIN ◽  
Bede MICKAN ◽  
Fayuan WANG ◽  
Ying ZHANG ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Arbuscular Mycorrhizal Fungi ◽  
Reciprocal Translocation ◽  
Mycorrhizal Fungi ◽  
Climate Changes ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Spore Density ◽  
The Tibetan Plateau ◽  
Colonization Frequency

Arbuscular mycorrhiza (AM) fungi are considered as an important factor in predicting plants and ecosystem responses to climate changes on a global scale. The Tibetan Plateau is the highest region on Earth with abundant natural resources and one of the most sensitive region to climate changes. To evaluate the complex response of arbuscular mycorrhizal fungi colonization and spore density to climate changes, a reciprocal translocation experiment was employed in Tibetan Plateau. The reciprocal translocation of quadrats to AM colonization and spore density were dynamic. Mycorrhizal colonization frequency presented contrary changed trend with elevations of quadrat translocation. Colonization frequency reduced or increased in majority quadrats translocated from low to high or from high to low elevation. Responses of colonization intensity to translocation of quadrats were more sensitive than colonization frequency. Arbuscular colonization showed inconsistent trend in increased or decreased quadrat. Vesicle colonization decreased with changed of quadrat from low to high elevations. However, no significant trend was observed. Although spore density was dynamic with signs of decreasing or increasing in translocated quadrats, the majority enhanced and declined respectively in descent and ascent quadrat treatments. It is crucial to understand the interactions between AM fungi and prairie grasses to accurately predict effects of climate change on these diverse and sensitive ecosystems. This study provided an opportunity for understanding the effect of climate changes on AM fungi.

scholarly journals Examining soil carbon uncertainty in a global model: response of microbial decomposition to temperature, moisture and nutrient limitation

2013 ◽  
Vol 10 (6) ◽  
pp. 10229-10269
Author(s):  
J.-F. Exbrayat ◽  
A. J. Pitman ◽  
Q. Zhang ◽  
G. Abramowitz ◽  
Y.-P. Wang
Keyword(s):  
Soil Carbon ◽  
Nutrient Limitation ◽  
Historical Change ◽  
Cmip5 Models ◽  
Earth System ◽  
Microbial Decomposition ◽  
Soil C ◽  
System Models ◽  
C And N ◽  
Earth System Models

Abstract. Reliable projections of future climate require land–atmosphere carbon (C) fluxes to be represented realistically in Earth System Models. There are several sources of uncertainty in how carbon is parameterized in these models. First, while interactions between the C, nitrogen (N) and phosphorus (P) cycles have been implemented in some models, these lead to diverse changes in land–atmosphere fluxes. Second, while the parameterization of soil organic matter decomposition is similar between models, formulations of the control of the soil physical state on microbial activity vary widely. We address these sources uncertainty by implementing three soil moisture (SMRF) and three soil temperature (STRF) respiration functions in an Earth System Model that can be run with three degrees of biogeochemical nutrient limitation (C-only, C and N, and C and N and P). All 27 possible combinations of a SMRF with a STRF and a biogeochemical mode are equilibrated before transient historical (1850–2005) simulations are performed. As expected, implementing N and P limitation reduces the land carbon sink, transforming some regions from net sinks to net sources over the historical period (1850–2005). Differences in the soil C balance implied by the various SMRFs and STRFs also change the sign of some regional sinks. Further, although the absolute uncertainty in global carbon uptake is reduced, the uncertainty due to the SMRFs and STRFs grows relative to the inter-annual variability in net uptake when N and P limitations are added. We also demonstrate that the equilibrated soil C also depend on the shape of the SMRF and STRF. Equilibration using different STRFs and SMRFs and nutrient limitation generates a six-fold range of global soil C that largely mirrors the range in available (17) CMIP5 models. Simulating the historical change in soil carbon therefore critically depends on the choice of STRF, SMRF and nutrient limitation, as it controls the equilibrated state to which transient conditions are applied. This direct effect of the representation of microbial decomposition in Earth System Models adds to recent concerns on the adequacy of these simple representations of very complex soil carbon processes.

scholarly journals Resolving ecological feedbacks on the ocean carbon sink in Earth system models

2020 ◽  
Author(s):  
David I. Armstrong McKay ◽  
Sarah E. Cornell ◽  
Katherine Richardson ◽  
Johan Rockström
Keyword(s):  
Climate Change ◽  
Carbon Sink ◽  
Biological Pump ◽  
Earth System ◽  
Temperature Dependent ◽  
System Models ◽  
Plankton Ecology ◽  
Ocean Carbon ◽  
The Impact ◽  
Earth System Models

Abstract. The Earth’s oceans are one of the largest sinks in the Earth system for anthropogenic CO2 emissions, acting as a negative feedback on climate change. Earth system models predict, though, that climate change will lead to a weakening ocean carbon uptake rate as warm water holds less dissolved CO2 and biological productivity declines. However, most Earth system models do not incorporate the impact of warming on bacterial remineralisation and rely on simplified representations of plankton ecology that do not resolve the potential impact of climate change on ecosystem structure or elemental stoichiometry. Here we use a recently-developed extension of the cGEnIE Earth system model (ecoGEnIE) featuring a trait-based scheme for plankton ecology (ECOGEM), and also incorporate cGEnIE's temperature-dependent remineralisation (TDR) scheme. This enables evaluation of the impact of both ecological dynamics and temperature-dependent remineralisation on the soft-tissue biological pump in response to climate change. We find that including TDR strengthens the biological pump relative to default runs due to increased nutrient recycling, while ECOGEM weakens the biological pump by enabling a shift to smaller plankton classes. However, interactions with concurrent ocean acidification cause opposite sign responses for the carbon sink in both cases: TDR leads to a smaller sink relative to default runs whereas ECOGEM leads to a larger sink. Combining TDR and ECOGEM results in a net strengthening of the biological pump and a small net reduction in carbon sink relative to default. These results clearly illustrate the substantial degree to which ecological dynamics and biodiversity modulate the strength of climate-biosphere feedbacks, and demonstrate that Earth system models need to incorporate more ecological complexity in order to resolve carbon sink weakening.

scholarly journals Biodiversity and distribution of arbuscular mycorrhizal fungi in Araucaria angustifolia forest

2007 ◽  
Vol 64 (4) ◽  
pp. 393-399 ◽  
Author(s):  
Milene Moreira ◽  
Dilmar Baretta ◽  
Siu Mui Tsai ◽  
Sandra Maria Gomes-da-Costa ◽  
Elke Jurandy Bran Nogueira Cardoso
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Root Colonization ◽  
Biological Diversity ◽  
Diversity Index ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Araucaria Angustifolia ◽  
Forest Sustainability ◽  
Shannon’S Diversity Index

Araucaria angustifolia (Bert.) O. Ktze. is an endangered Brazilian coniferous tree that has been almost exterminated in the native areas because of uncontrolled wood exploitation. This tree has been shown to be highly dependent on arbuscular mycorrhizal fungi (AMF) and, therefore, AMF may be essential for forest sustainability and biological diversity. Root colonization, density and diversity of AMF spores were assessed in two Araucaria forest stands at the State Park of Alto Ribeira (PETAR), at two sampling dates: May and October. A comparison was made between a mature native stand composed of Araucaria trees mixed into a variety of tropical trees and shrubs, without any sign of anthropogenic interference (FN) and an Araucaria stand planted in 1987 (R), which has been used as a pasture. Assessments included percent root colonization, AMF spore numbers and species richness, Simpson's dominance index (Is), and Shannon's diversity index (H). Mycorrhizal root colonization did not differ between ecosystems in May. In October, however, the native stand (FN) presented a higher colonization than the planted forest (R), and the root colonization was more intense than in May. When considering both sampling periods and forests, 27 species of AM fungi, with higher numbers of spores in FN than in R were found. Canonical discriminant analysis (CDA) indicated Shannon's diversity index as the ecological attribute that contributed the most to distinguish between forest ecosystems, with higher value of H in FN in relation to R. CDA showed to be a useful tool for the study of ecological attributes.

scholarly journals An Overview of CMIP5 and the Experiment Design

2012 ◽  
Vol 93 (4) ◽  
pp. 485-498 ◽  
Author(s):  
Karl E. Taylor ◽  
Ronald J. Stouffer ◽  
Gerald A. Meehl
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Global Climate ◽  
Experiment Design ◽  
Global Climate Models ◽  
Model Output ◽  
Earth System ◽  
Intergovernmental Panel ◽  
System Models ◽  
Earth System Models

The fifth phase of the Coupled Model Intercomparison Project (CMIP5) will produce a state-of-the- art multimodel dataset designed to advance our knowledge of climate variability and climate change. Researchers worldwide are analyzing the model output and will produce results likely to underlie the forthcoming Fifth Assessment Report by the Intergovernmental Panel on Climate Change. Unprecedented in scale and attracting interest from all major climate modeling groups, CMIP5 includes “long term” simulations of twentieth-century climate and projections for the twenty-first century and beyond. Conventional atmosphere–ocean global climate models and Earth system models of intermediate complexity are for the first time being joined by more recently developed Earth system models under an experiment design that allows both types of models to be compared to observations on an equal footing. Besides the longterm experiments, CMIP5 calls for an entirely new suite of “near term” simulations focusing on recent decades and the future to year 2035. These “decadal predictions” are initialized based on observations and will be used to explore the predictability of climate and to assess the forecast system's predictive skill. The CMIP5 experiment design also allows for participation of stand-alone atmospheric models and includes a variety of idealized experiments that will improve understanding of the range of model responses found in the more complex and realistic simulations. An exceptionally comprehensive set of model output is being collected and made freely available to researchers through an integrated but distributed data archive. For researchers unfamiliar with climate models, the limitations of the models and experiment design are described.

scholarly journals Detection of Arbuscular Mycorrhizal Fungi in the Roots of Strawberry Plants Fertilized with Organic Bioproducts

2012 ◽  
Vol 77 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Anna Lisek ◽  
Lidia Sas Paszt ◽  
Beata Sumorok
Keyword(s):  
Plant Growth ◽  
Arbuscular Mycorrhizal Fungi ◽  
Nested Pcr ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Universal Primers ◽  
Mineral Fertilizers ◽  
Reaction Products ◽  
The Impact

Summary In organic farming, mineral fertilizers are replaced by various preparations to stimulate plant growth and development. Introduction of new biopreparations into horticultural production requires an assessment of their effects on the growth and yielding of plants. Among the important indicators of the impact on plants of beneficial microorganisms contained in bioproducts is determination of their effectiveness in stimulating the growth and yielding of plants. Moreover, confirmation of the presence of arbuscular mycorrhizal (AM) fungi in the roots and plant growth promoting rhizobacteria (PGPR) in the rhizosphere is also necessary. In addition to conventional methods, molecular biology techniques are increasingly used to allow detection and identification of AM fungi in plant roots. The aim of this study was identification and initial taxonomic classification of AM fungi in the roots of ‘Elkat’ strawberry plants fertilized with various biopreparations using the technique of nested PCR. Tests were performed on DNA obtained from the roots of ‘Elkat’ strawberry plants: not fertilized, treated with 10 different biopreparations, or fertilized with NPK. Amplification of the large subunit of ribosomal gene (LSU rDNA) was carried out using universal primers, and then, in the nested PCR reaction, primers specific for the fungi of the genera Glomus, Acaulospora, and Scutellospora were used. Colonization of strawberry roots by arbuscular mycorrhizal fungi was determined on the basis of the presence of DNA fragments of a size corresponding to the types of the fungi tested for. As a result of the analyses, the most reaction products characterizing AM fungi were found in the roots of plants treated with the preparation Florovit Eko. The least fragments characteristic of AM fungi were detected in the roots of plants fertilized with NPK, which confirms the negative impact of mineral fertilizers on the occurrence of mycorrhizal fungi in the roots of strawberry plants. The roots of plants fertilized with Tytanit differed from the control plants by the presence of one of the clusters of fungi of the genus Glomus and by the absence of a cluster of fungi of the genus Scutellospora. In the roots of plants treated with other biopreparations there were reaction products indicating the presence of fungi of the genera Glomus, Scutellospora and Acaulospora, like in the roots of the control plants. The results will be used to assess the suitability of microbiologically enriched biopreparations in horticultural production.

Impact of improved land model depth and hydrology on climate change projections

2020 ◽  
Author(s):  
Norman Steinert ◽  
Fidel González-Rouco ◽  
Stefan Hagemann ◽  
Philipp de Vrese ◽  
Elena García-Bustamante ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Surface ◽  
Earth System ◽  
Energy Propagation ◽  
Near Surface ◽  
Bottom Boundary ◽  
System Models ◽  
Model Component ◽  
And Storage ◽  
Earth System Models

<p>The representation of the thermal and hydrological state in the land model component of Earth System Models is crucial to have a realistic simulation of subsurface processes and the coupling between the atmo-, lito- and biosphere. There is evidence suggesting an inaccurate simulation of subsurface thermodynamics in current-generation Earth System Models, which have Land Surface Models that are too shallow. In simulations with a bottom boundary too close to the surface, the energy propagation and spatio-temporal variability of subsurface temperatures are affected. This potentially restrains the simulation of land-air interactions and subsurface phenomena, e.g. energy/moisture balance and storage capacity, freeze/thaw cycles and permafrost evolution. We introduce modifications for a deeper soil into the JSBACH soil model component of the MPI-ESM for climate projections of the 21st century. Subsurface layers are added progressively to increase the bottom boundary depth from 10m to 1400m. This leads to near-surface cooling of the soil and encourages regional terrestrial energy uptake by one order of magnitude and more. <br>The depth-changes in the soil also have implications for the hydrological regime, in which the moisture between the surface and the bedrock is sensitive to variations in the thermal regime. Additionally, we compare two different global soil parameter datasets that have major implications for the vertical distribution and availability of soil moisture and its exchange with the land surface. The implementation of supercool water and water phase changes in the soil creates a coupling between the soil thermal and hydrological regimes. In both cases of bottom boundary and water depth changes, we explore the sensitivity of JSBACH from the perspective of changes in the soil thermodynamics, energy balance and storage, as well as the effect of including freezing and thawing processes and their influence on the simulation of permafrost areas in the Northern Hemisphere high latitudes. The latter is of particular interest due to their vulnerability to long-term climate change.</p>

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